4 ms·
Would it make a difference with SSD drives?
by hamoid 14y ago
Would it make a difference with SSD drives?
- diggan 14y agoNo, it moves the files used in the startup to a closer sector and won't speed up your booting time if you're using SSD discs.
- rbanffy 14y agoBy placing the files together in the memory you may get some extra performance, but it depends on how your SSD is internally organized - you may have some locality effects if the drive pre-fetches more than the block you called for into a cache faster than the flash memory.
- jeltz 14y agoSequential reads are faster than random even on SSD drivers, so it could help but I am not sure how much.
- Iv 14y agoOh ? Why is that ? SSD still need to address every memory block, don't they ? Or do they have a faster DMA-like mode where you can send the instruction "give me the next 96KB starting at address X ?
- lucian1900 14y agoSSDs exhibit the same sort of cache locality RAM does. When a region is accessed, a larger chunk is fetched and cached just in case it's needed later.
- nuje 14y agoYes, and the OS readahead also helps. You can see the random vs sequential difference in any ssd review, eg http://thessdreview.com/our-reviews/ocz-vertex-3-240gb-max-iops-review-as-ssd-tests/ http://thessdreview.com/our-reviews/ocz-vertex-3-240gb-max-i... shows 18 MB/s in random reads vs 500 MB/s sequential reads.
- diggan 14y agoI'm not sure if a SSD drive have any moving parts and therefor will not benefit from E4rat.
- wtallis 14y agoWith an SSD, the bottleneck for booting is usually hardware detection and initialization, not reading data off the disk. My system takes about 4-5 seconds from the time the bootloader hands off control to the kernel to the time the kernel starts executing the initrd, and another 6-7 seconds to mount the SSD and hard drive, establish the network connection, start system services, and present a login prompt (though starting X and changing resolutions takes another second or two on top of that). I probably can't make that more than 20% faster without getting a faster DHCP server or tweaking various delays and timeouts that exist for good reasons.